LCN2 and major depressive disorder: The suppression of excess Lcn2 is thought to be a therapeutic target for chronic neuroinflammatory and neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases, depression, schizophrenia and autism [70], suggesting that theanine may be important in protecting the brain not only from stress but also from many chronic neuroinflammatory and neurodegenerative diseases.